ESE's works engine tuner

[TZ350]

If we can change the question to have I beaten Av before? Yes. When she was a kid.

I have beaten Av before too, when I was chasing her and she fell off in the rain. I felt conflicting emotions about feeling pleased to have beaten a 13 year old girl who had just bounced along the track...

[Frits Overmars]

I have beaten Av before too, when I was chasing her and she fell off in the rain. I felt conflicting emotions about feeling pleased to have beaten a 13 year old girl who had just bounced along the track...

I know the feeling. In my first 500cc race the guy I was chasing fell off and my first thought was: "One down, only about 20 to go".
My second thought, about one second later, was: "Shame on me, one shouldn't think that way".
I suppose many of us have experienced similar feelings. Or is it just my twisted brain?

[Carel H]

Attachment 341855

Because when you throttle off, the pipe resonance collapses and so does the airflow. Current 2S EFI systems don't cope well with dramatic changes in pipe suction.

Currently there is no proven method I know of that can detect this change of airflow in a high performance single cylinder racing two stroke.

Throttle is also an input and the trigger off an event.

[speedpro]

That's a good point. What about the reverse of an accelerator pump, or acceleration enrichment in FI terminology? A timed "reduction" in the calculated fuel when TPS changes from very low value to some other value. Long enough to kick the pipe back into life without drowning the motor.
Factors would be:
Amount of reduction, in %
Duration of reduction, in seconds
Slope of reduction, determined by the above, or simply on & off.

[F5 Dave]

I have beaten Av before too, when I was chasing her and she fell off in the rain. I felt conflicting emotions about feeling pleased to have beaten a 13 year old girl who had just bounced along the track...

It's a win Rob. I've beat Dennis on my 50 he on a fast 100. There might have been reasons but I feel they aren't important.

[Lurifax]

So, . . What sort of throttle response is required on a saw?

My experince with chainsaws and felling a tree that the chainsaw is either ON or OFF. You allways use full power and keep throttle wide as you are cutting the tree. A sharp chain is also a must, if you sharpen it wrong the cut will turn either side and then you are halving the tree...

[JanBros]

My experince with chainsaws and felling a tree that the chainsaw is either ON or OFF.

indeed, it doesn't need "instant response". it just needs to run great at WOT, it must have good idle and it must respond well to "quickly opening the throttle" . It never has to respond well at smoothly opening the throttle after having being run with closed throttle at at "slowly descending revs halfway the rev-range"
what it does very bad is (or "dangerous for the engine") is run wthe the throttle "in between" as their pumper carbs do not have something to regulate the mixture at "half throttle". IBEA makes pumper carb's that have a seperate adjustment for that.

[F5 Dave]

So chainsaw fuel injection may be not a relevant model to follow for the racing motorbicycle.

[Grumph]

So chainsaw fuel injection may be not a relevant model to follow for the racing motorbicycle.

Depends if you count the X games bikes as racers....The abilty to run inverted and through extreme G loadings is certainly required there...
And from what I've seen, midrange control isn't an issue, LOL.

[wobbly]

When was the last time you powered into a tree cut at full throttle, backed right off with the chain still moving , then went back to 1/3 throttle
and expected it to react smoothly , such that your boots didnt loose grip with the ground .
The real issue though is that the so called " box " muffler reacts nothing like a tuned pipe during these transient response phases.

[SwePatrick]

V force told me their reeds were not compatible with ethanol, perhaps its the same with methanol.
You need a steel rotary valve😆

Newer V-force reeds sold lately is like rubberpetals when using them with methanol, no good.

[peewee]

if you want good reeds for methanol and nitro go to this place carbontech.com

[lohring]

We've built a lot of model boat racing 26 cc engines that started life on weedeaters. Like chain saws they run pumper carbs, can mufflers, and are either on or off in stock form. We want a tuned pipe engine with almost twice the power that can be throttled a little and idles well. A typical running start involves a slow speed approach to the line with a quick transition to full throttle. A lot of engines will die despite heavier flywheels and carb pop off tuning. Bored out stock carbs don't help with the pressure signal to the diaphragm either. We've even blocked passages with super glue in a Tillison carb to get a rich enough low speed mixture and a lean enough full throttle mixture.

I keep thinking that someone will build a simple fuel injection system that can be easily adjusted to overcome these issues. Even throttle body injection should be better. Probably cost keeps manufacturers from developing injection over carbs. I keep following the more sophisticated injection systems worked on here for hints. Meanwhile YS model pattern engines run a very simple injection system with CD ignition.

Lohring Miller

[husaberg]

We've built a lot of model boat racing 26 cc engines that started life on weedeaters. Like chain saws they run pumper carbs, can mufflers, and are either on or off in stock form. We want a tuned pipe engine with almost twice the power that can be throttled a little and idles well. A typical running start involves a slow speed approach to the line with a quick transition to full throttle. A lot of engines will die despite heavier flywheels and carb pop off tuning. Bored out stock carbs don't help with the pressure signal to the diaphragm either. We've even blocked passages with super glue in a Tillison carb to get a rich enough low speed mixture and a lean enough full throttle mixture.

I keep thinking that someone will build a simple fuel injection system that can be easily adjusted to overcome these issues. Even throttle body injection should be better. Probably cost keeps manufacturers from developing injection over carbs. I keep following the more sophisticated injection systems worked on here for hints. Meanwhile YS model pattern engines run a very simple injection system with CD ignition.

Lohring Miller

Lohring i posted a while ago mirco fuel injection stuff a university student was selling Pico or something.
https://www.popularmechanics.com/car...tors-15682450/
https://www.fastcompany.com/3004342/...-fraction-cost
http://spark.annarborusa.org/feature...4Feature2.aspx

[TZ350]

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